The present invention is directed to linkages for controlling switches and more particularly to a linkage for use as a double throw switch for controlling two switches mounted in the same enclosure so that only one switch can be on at any given time.
Switching apparatus generally referred to as a double throw switch is commonly used to alternatively connect one of two load devices to a source of electric power or to connect a single load device alternatively to one of two separate sources of electric power. For example, two lines coming into a switch tied to one load coming out of the switch as in a system that has an emergency power generator to switch from normal power source to the emergency generator. Another example is one line coming into a switch tied to two loads coming out of the switch as in a system that has a backup pump that needs to operate when the main pump is off line. The two switch mechanisms are tied together with a linkage. The linkage allows only one switch to be turned on at a time. Prior linkages typically are assembled using multiple slots in a plate which is secured to a framework by multiple fasteners or rivets which slide in the plurality of slots.
There is a need for a double throw switch linkage that requires fewer parts for assembly thereby reducing costs and complexity.
There is provided a double throw switch linkage for coupling two switch apparatuses together in an enclosure. Each switch apparatus is coupled to the switch mechanism having a switch mechanism lever arm. The double throw switch linkage comprises an interlock housing, with the interlock housing defining a pair of actuator plate slots and a first orifice and a second orifice. Each orifice is configured to provide unimpeded passage of each switch mechanism lever arm. An actuator plate is slidingly mounted in the actuator plate slots. The actuator plate is free floating in the interlock housing. The actuator plate defines a first switch slot, a second switch slot, and a driver arm slot. Each switch slot is configured to guide a pin mounted on each switch mechanism lever arm. A lever arm assembly is mounted on a sidewall of the enclosure with the lever arm assembly including a lever arm coupled to a driver arm. The driver arm is configured to engage the driver arm slot and the actuator plate. When the lever arm is moved it translates a force to the actuator plate which closes one switch mechanism and maintains the other switch mechanism in an open position.
There is also provided an electric double switch comprising an enclosure having at least one sidewall, a bottom wall and a cover. A first switch apparatus, including a first switch mechanism having a lever arm is mounted in the enclosure. A second switch apparatus, including a second switch mechanism having a lever arm, is mounted in the enclosure. A double throw switch linkage is coupled to each of the first and second switch apparatus. The double throw switch linkage comprises an interlock housing, with the interlock housing defining a pair of actuator plate slots and a first orifice and a second orifice. Each orifice is configured to provide unimpeded passage of each switch mechanism lever arm. An actuator plate is slidingly mounted in the actuator plate slots. The actuator plate defines a first switch slot, a second switch slot, and a driver arm slot. Each switch slot is configured to guide a pin mounted on each switch mechanism lever arm. A lever arm assembly is mounted on the sidewall of the enclosure. The lever arm assembly includes a lever arm coupled to a driver arm, with the driver arm configured to engage the driver arm slot in the actuator plate. Upon movement of the lever arm, the lever arm translates a force to the actuator plate which closes one switch apparatus and maintains the other switch apparatus in an open position.
Also provided is a method for interlocking two switch apparatus mounted in an enclosure. Each switch apparatus has a switch mechanism including a switch mechanism lever arm and the enclosure has a cover and a sidewall. The method comprises the steps of providing an interlock housing. The interlock housing defining a pair of actuator plate slots and a first orifice and a second orifice, with each orifice configured to provide unimpeded passage of each switch mechanism lever arm. Mounting the interlock housing in the enclosure adjacent to the switch mechanisms. Providing an actuator plate, with the actuator plate defining a first switch slot, a second switch slot and a driver arm slot. Each switch slot is configured to guide a pin mounted on each switch mechanism lever arm. Inserting the actuator plate in each actuator plate slot for free sliding movement. Aligning the pin on each switch mechanism arm in one of the first and second switch slots in the actuator plate. Mounting a lever arm assembly on the sidewall of the enclosure, with the lever arm assembly including a lever arm coupled to a driver arm. Aligning the driver arm to engage the driver arm slot in the actuator plate. Moving the lever arm to translate a force to the actuator plate wherein one switch apparatus is closed and the other switch apparatus is maintained in an open position. An alternative embodiment for the method includes the step of providing an interlock release mechanism coupled to the cover and the interlock housing, wherein the cover can be opened if one of the switch apparatus is closed.